Adjustable mounting optoendstop the Z axis, control without the help of a screwdriver. The scale of the Knob equivalent to 0.05 mm in height.
Look here: http://www.thingiverse.com/thing:21654
Print model, correct holes. Print Scale on the sticker and glue on endstopholder and Knob as shown in the picture. Knob must stick to the M4 screw before final assembly.
1x screw M4x40mm
3x M4 washers
2x screw M3x20mm
2x M3 nuts
2x M3 washers
1x spring (on the screw M4)